Difference of neural connectivity for motor function in chronic hemiparetic stroke patients with intracerebral hemorrhage

Difference of neural connectivity for motor function had been studied by observation of neural activity within gray matter and nucleus using functional neuroimaging techniques. Diffusion tensor imaging (DTI) by a probabilistic tracking is useful for exploration of structural connectivity in the brain. We attempted to investigate difference of neural connectivity for motor function of the affected hand in chronic hemiparetic patients with intracerebral hemorrhage (ICH). Forty-four patients with ICH and 31 normal control subjects were recruited. Diffusion tensor imaging was acquired using a sensitivity-encoding head coil at 1.5 T. Motor function was evaluated using the motricity index (MI) for hand and Modified Brunnstrom Classification (MBC). The presence or absence of a connection was confirmed between the precentral knob of the affected hemisphere and seven areas. Compared with healthy subjects, the patient group showed lower connectivity to the contralesional primary motor cortex, ipsilesional basal ganglia, ipsilesional thalamus, contralesional cerebellum, and ipsilesional medullary pyramid in the affected hemisphere (p < 0.05). Connections to the ipsilesional basal ganglia, ipsilesional thalamus, and ipsilesional medullary pyramid showed positive correlation with MI and MBC (p < 0.05). We found difference of neural connectivity for motor function between chronic hemiparetic patients with ICH and control subjects. Our results suggest that the motor function of the stroke patient is related to neural connectivity between the ipsilesional M1 and the ipsilesional medullary pyramid, ipsilesional basal ganglia, and ipsilesional thalamus.

► We investigated changes of neural connectivity for motor function in chronic hemiparetic patients.
► The patient group showed lower connectivity to the ipsilesional basal ganglia, thalamus, and medullary pyramid.
► Connections to the ipsilesional basal ganglia, thalamus, and medullary pyramid showed positive correlation with motor function.
► For probabilistic tracking, the higher threshold in this study revealed relatively delicate connectivity.
► The correlation coefficient for the non-zero streamline threshold was lower than 10 and 25 streamlines.